ASHRAE Guideline 13 — Alarm Management

ASHRAE 90.4 / TIA-942

Branch circuit monitoring is required for capacity planning and to detect load imbalances. ASHRAE 90.4 mandates metering of electrical distribution in data centers, and most Tier III+ designs require per-circuit monitoring.

ASHRAE Fundamentals Handbook — Hydronic System Design

The decoupler pipe should not have isolation valves — this is correct as installed. However, the decoupler pipe connections are spaced only 2 pipe diameters apart. Connections must be spaced at least 6-10 pipe diameters apart to prevent flow turbulence and ensure proper hydraulic separation.

ASHRAE Guideline 12 — Minimizing the Risk of Legionellosis

Without automatic blowdown control, condenser water cycles of concentration are unmanaged. Manual blowdown is unreliable and either wastes water (over-blowing) or allows mineral concentration to build (under-blowing). An automatic conductivity controller with a motorized blowdown valve is required to maintain proper cycles of concentration (typically 3-6 cycles).

ASHRAE Guideline 13 — Data Management

Storing trend data only in field controllers risks data loss when controllers are reset or lose power. Trend data should be archived to the BAS server or a dedicated historian. Controller memory is limited and will overwrite oldest data.

ASHRAE Guideline 36 — Chiller Staging

Staging a lag chiller immediately at 100% lead capacity causes hunting and instability. A time delay (typically 10-15 minutes) and sustained load confirmation are required to prevent short-cycling. ASHRAE Guideline 36 specifies staging criteria with time delays and load verification.

ASHRAE Guideline 36 — Cooling Coil Control

Cooling coil control valves should fail closed (spring return to closed) on loss of signal or power. Failing open causes uncontrolled cooling and potential freezing of downstream coils or spaces.